Variable-temperature method of curing and treating tobacco



i ALFRED CHARLES BUENBOD, 0] NEW YORK, H. Y.

vaamnn-rmmruas names or come aim ramrme ronacco.

ll'o Pravdng. Application fled Inch 14, 1817,8erla1 No. 164,843. Renewed mimeti- 81, 1984.

To all whom it my concern:

Be it known that I, ALFRED. Cnumna. h

BUENSOD, a citizen of the United States of America, residing in the city, county, and State of New;York, have invented a new and useful Variable-Tem erature Method of Curing and Treating To acco, of which the following is a full, clear, and esact descripparticularly to treatment such as outlined in my co-pending applications Serial ,Nos. 154842 and 154,844, each filed March 14 191%, each of which describes-a method of curing and treating tobacco, the former of which haseventuated into. .Patent Number 1,339,375, Jan-3, 1923.

It is well known to those the art, that all tobacco, before it can be placed upon the market, must be cured. This treatment is such as to bring about certain chemical chan in the composition of the leaf; namely, e development of the desired color, the regulation of the temperature retaining capacity, the control of the texture, fire holdingcapacityand-the elasticity, and the production; of the proper keeping qualities of the tobacco.

When-the green tobacco leaf is hung in an absolutely dark chamber, the action of the rays of light and the moisture supply through the root system bein cut off, a period of starvation sets in, an the reserve suppl of food stored in the leaf is consume It is necessary that tobacco be cured in the absence of the direct or the indirect rays of sunlight in order to extend the starving process. This is so because plant life is-dependent upon a food supply, a water supply, and the agencies of the rays of sunlight for its development, and in curmg, we deprive the plant of its source of water and its food supply and must also deprive it of the agencies of light. If light is present, al-. though the food and water supply has been terminated, the rays of light acting upon the tobacco might cause a further growth of the tobacco by utilizing the water supply of the leaves and the food stored up therein. The

leaf always contains certain enzymes which take an active part in the chemical changes throughout the curing process, and, in the period of cell starvation, they are greatly increased. The formation of ,the color ofthe cured tobacco leaf is entlrely due to the oxidation of the cell substance through t emedium of an enzyme. These coloring enzymes act upon the cell substance and producethe various final colors in the leaf, de pending upon the duration of the action, the amount of enzymes present, and the amount of moisture still retained by the cells, which .moisture acts as a carrier.

This oxidation ma be so controlled as to produce a lemon e ow, an orange, a brown, a greenishrown, or a dark. brown color. In the curing process, the intensity of the chemical actionsand the time necessary for a thorough cure are dependent-upon the temperatures used. The excessmoisture of the leaf is l iberatecl and must be carried away as the leaf 1s gradually starved and ,colored. If the .molsture in the leaf is extracted rapidly, or if the leaf is subjected to unfavorable temperatures or oisons, the cells would be prematurely kll ed before the starch could be dissolved and the green-color would thereby be set in the leaf. If the coloring enzymes werestill alive they would act on the cell substance and produce colors showing over the green color of the leaf. To obtain the yellowcolor, it is necessary to slowly starve the leaf and to allow sufficient time. for the starch to be dissolved, thereby causing the natural death ofthe cells. v

In some types of tobacco, particularly that which is used for cigars, enzymes are required for further treatment of the leaf and hence the temperature used in the curing must not be high enough to kill them.

Afterthe tobacco has been thoroughly cured, the moisture content thereof must be increased to a proper amount. This increase in moisture is necessary for two reasons: first, in order that breakage may not occur when handling thetobacco; secondly, that the tobacco may have the proper amount of moisture for further treatment. In the case of cigar tobacco a moisture'content of 25% must be supplied.

The principal object of my invention has been to provide a continuous method of ouring and treating tobacco, which preferably is carried on in darkness, and under conditions in which the temperature and relative humidity ,may be absolutely governed, so that the chemical changes going on in the leaf may be easily controlled, thereby producing the desired properties in the leaf.

In carrying out my invention, the een tobacco leaves are suspended in a suitable curing appai atusland subj continuousl circulating air currents of a certain. pro etermined temperature and relative umidity. In my present method, the temperature iof the air 1n -the; cu ring process isgradually raised and its percentage of relative humidity is maintained substantially at a uniform percenta e until the tobacco has reached the desired stage, whereupon the temperature is decreased and'-the"'relativehumidity raised, thus supplying the 'neces- 'sary moisture to avoid breakage'in handling or for furthertreatment;

In practical prefer to use-air at a temperature of from 70 to 80 F. andat a rela tive-humidity of 'fromf 78% to 82%." The method is carried on under these conditions for a len h oftime sui'n'cient to consume the surplus cod contained'in'the leaf and cause age or be in proper condition for further the air 5 is the death of the cells.--Tl i e temperature of process. Before the tobaccoisireiiiovedfromthe apparatus, thetemperature'is' lowered to from 75 to 85F. and the humidity is 'raised' to from 80%t0 8 thus' givingfto the 'to-' treatment. I The above'imethod may bemodified slightly by maintaining a"'substantially constant relative humidity throughout the major portion of the curing the humidity just is complete refer to start with air at a temperature of F. and a relative humidity of 82%. The temperature of the air is. raised to 90 F. while the relative humidity thereof is maintained at 82%. The temperature is now gradually increased to from 160 to 170 and the humidity islowered to 65%,then the temperature is lowered to from to 85 F. and the humidi increased to-from to to replace in the tobacco the necessary moisture content.

Having thus described my I claim 1s:

1. A method of curing and treatin to bacco 'which consists in subjectin it, or a invention, what 'sufiicient time, to air currents havmg a temperature of from 70 to 80 F. and a relative humidity of from 7 8% to 82%, and then gradually raising the temperature of the air to from to F.,' while'maintaimingthe relative humidity thereof as before,

untilflthe surplus food content in the leaf has been consumed and the cellshave died.

2. A method of curing and treatin tobacco which consists in subjecting it, or a adually raised to from 90 to 100 F; at t e yellowing" stage of the tobacco. The temperatureiscontinuously increased until it reaches to" thejhumidity having been-maintained atsubstantially' the piocess and then lowering" fore the curing rocess" In this modified met od, I-

sufiicient time, to air'currents havin a tema rela- ,tiveQhumidityof from 78% to 82%, then perature of from 70 to 80-F. an

gradually raising the temperature of the A air to from 90 .to 100 -F., while .mai-ntain-. 1ng therelative humidity thereof as before,

until the surplus food content in the leaf v has been consumed and the cells-have died, then vcontinuously mcreasin the temperature of such air currents until the tem raturereaches a point between 120 and 130 F., while still maintainin the same percentageof relative humidity thereof, and then owering the temperature of the air to from 75 to 85 F. and raising the relative humidity thereof to from 80% to 85%, until the necessary moisture content has been supplied for avoiding breakage in handling or 'for further treatment.

3. A method of curing and treat' bacco which consists'in subjecting it, or a sufficient time, to air currents havmga' temperature of 70 F; and arelative humidity '4; A'- method; of 'curing and' treatin to- "bacco which consists in subjecting it, or a suflicient time,to air currents havmg a temperature of 70F. and 'a relative humidity of 82%, then gradually raisin the temperature of the air to 90 F., w ile maintaining the relative humidity thereof as before, until the surplus food content in the leaf has been consumed and the cells have died, then continuously increasing the temperature of such air currents until the temperature reaches a point between and F. and lowering the relative humidity to 65%, and then lowering the temperature of the air to from 75 to 85 F. and raising the relative humidity thereof to from 80% to 85%,)until the necessary moisture content has eenadded for avoiding breakage in handling or for further treatment.

5. A method of curing and treating tobacco which consists in subjecting it in darkness, for a suflicient time, to air currents having a temperature of from 70 to 80 F. and a relative humidity of from 7 8% to 82%, and then gradually raising the temperature of the air to from 90 to 100 F., while' maintaining the relative humidity thereof as before, until the surplus food content in the leaf has been consumed and the cells have died. v

6. A method of curin and treatin to bacco which consists in su jecting it in darkness, for a sufiicient time, toair currents leaf has been consumed and the cells have died, then continuously increasing the temperature of such air currents until the temperature reaches a point between 120 and 130 F., while still maintainingthe 'same percentage of relative humidity thereof, and then lowering the temperature of the air to from to 85 F. and raising the relative humidity thereof to from to until the necessary moisture content has been supplied for avoiding breakage in handling or for further treatment.

a 7. A method of curing and treating tobacco which consists in subjecting it in darkness, for a suflicient time, to air currents having a temperature of 70 F. and a relative humidity of 82%, and then gradually raising the temperature of the air to F., while maintaining the relative humidity thereof as before, until the surplus food content in the leaf has been consumed and the cells have died.

8. A method of curing and treatin tobacco which consists in subjecting it in gar ness, for a sufficient time, to air currents having a temperature of 7 0 F. and a relative humidity of 82%, then gradually raising the temperature of the air to 90 F.,

while maintaining the relative humidity thereof as before, until the surplus food content in the leaf has been consumed and the cells have died, then continuously increasing the temperature of such air currents until the temperature reaches a point between and F. and lowering the relative humidity to 65%, and then lowering the temperature of the air to from 75 to 85 F. and raising the relative humidity thereof to from 80% to 85%, until the necessary moisture content has been added for avoiding breakage in handling or for further treatment.

In testimony whereof I have hereunto signed my name.

ALFRED CHARLES BUENSOD. 

